Post-World War I

The League was suspended for four seasons during World War I and resumed in 1919 with the First and Second Divisions expanded to 22 clubs. On resumption West Bromwich Albion (1919–20) and Burnley (1920–21), both original 12 clubs, won their first-ever titles (in Albion's case their only title to date).
In 1920, leading clubs from the Southern League joined the League to form a new Third Division, which in 1921 was renamed the Third Division South upon the further addition of more clubs in a new Third Division North. One club from each of these divisions would gain promotion to the Second Division, with the two relegated clubs being assigned to the more appropriate Third Division. To accommodate potential difficulties in this arrangement, clubs in the Midlands such as Mansfield Town or Walsall would sometimes be moved from one Third Division to the other.
Following this burst of post-war growth, the League entered into a prolonged period of relative stability with few changes in the membership, although there were changes on the pitch. In 1925, a new offside law reduced the number of opponents between the player and the goal from three to two, leading to a large increase in goals, and numbers on shirts were introduced in 1939.
Between 1923 and 1926, Huddersfield Town achieved the first feat of winning three consecutive league titles (and never won another one though they finished as runners-up for the following two years). This was equalled by Arsenal between 1932 and 1935, during a period from 1930 to 1938 in which they won five titles out of eight.
Manchester City (1936–37) became the only other club to be added to the list of Football League winners prior to the outbreak of World War II; the fourteenth club to achieve the feat since 1888-89.